Department of Paediatrics, University of Calgary, Alberta, Canada.
The change in DNA responsible for partial hypoxanthine-guanine phosphoribosyltransferase (HPRT) deficiency in three brothers has been determined by polymerase chain amplification and sequencing. An A-to-G substitution at base 155 in exon 3 predicts a change in aspartic acid 52 to glycine. Allele-specific polymerase chain amplification verified the presence of the mutation in genomic DNA and provides a means of direct diagnostic assay.